Shopping Cart – Part 3

Test-Driven Development: write tests before writing code.

Unit testing results in modular code. Modular code is:

• easy to test.
• immune to bugs.
• easy to understand.
• scalable.

Task 1

1. Create a test that fails

Write a unit test named removedItemTest. removedItemTest asserts that an item gets removed after being sold.

Inside Cart.java, write code to make the test fail.

  /**
   * Function name: remove
   * @param name
   * 
   * Inside the function:
   *   1. nothing
   */

2. Make the test pass

Write code inside Store.java to make the test pass.

 /**
  * Function name: remove
  * @param name
  * 
  * Inside the function:
  *   1. loop runs through the size of the ArrayList.
  *   2. removes the item that matches the name passed in. 
  */

3. Refactor

• Can remove be simpler?

Yes. removeIf offers a better way to remove elements. It removes elements that match the "predicate". In other words, elements for which the boolean is true.

removeIf expects a Lambda Expression.

ArrayList.removeIf(Lambda Expression)

The lambda expression for removeIf:

1. receives each element as a parameter.
2. has an arrow that points to code.
3. returns a boolean.

Important: As you refactor, run the unit test to make sure there aren't bugs.

Good Luck